<?php
use think\Db;

function mobile2dduserid($mobiles){
    $user = Db::name('dduser')->where('mobile','in',$mobiles)->select();
    if(!empty($user)){
        $userids = "";
        foreach ($user as $data){
            $userids .= $data['userid'] . ",";
        }
        return $userids;
    }
}